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Reasons for the Seasons Chapter 17.1. Nearly 150 million kilometers separate the sun and Earth, yet solar radiation drives Earth's weather. Figure 1.1. Does the distance from the Sun make the Seasons?. NO The Earth is actually farther away from the Sun when we have our Summer.
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Nearly 150 million kilometers separate the sun and Earth, yet solar radiation drives Earth's weather. Figure 1.1
Does the distance from the Sun make the Seasons? • NO • The Earth is actually farther away from the Sun when we have our Summer.
Reason for the Seasons 1. The Earth’s tilt causes the seasons • It is tilted at 23.5 degrees
The angle of the sun’s radiation (Insolation) hitting the Earth impacts the climate or temperature.
If the tilt were the only factor, then every location on Earth would have one season and it would never change.
2. Earth’s Revolution • Causes the Suns rays to strike at different locations as the Earth orbits the Sun.
When northern hemisphere is facing the sun: •Summer Solstice (June 21st or 22nd )
SUMMER SOLSTICE • Most direct rays over Northern Hemisphere • •Striking at Tropic of Cancer 23.5° N. • Light = 15 hours (about 14.27 (NC) Dark = 9 hours
Antarctica is completely dark for 24 hours and the Arctic is completely light for 24 hours!!!
EQUAL amounts of daylight and darkness everywhere. • Direct rays over Equator: • Light = 12 hoursDark = 12 hours
Winter Solstice - December 21-22 • SHORTEST DAY !!! • Most direct rays over Southern hemisphere•Striking at Tropic of Capricorn 23.5°S • Light = 9 hours Dark = 15 hours
EQUAL amounts of daylight and darkness everywhere. • Direct rays over Equator: • Light = 12 hours Dark = 12 hours
The Southern Hemisphere has opposite Seasons than us . . . WHY?
Light - Year • The unit used to measure stellar (star) distance. • The distance that light travels in one year. • 9.5 x 1012 kilometers a year. • 180,000 miles per second.